ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/drivers/base/devcoredump.c b/marvell/linux/drivers/base/devcoredump.c
new file mode 100644
index 0000000..e9398bc
--- /dev/null
+++ b/marvell/linux/drivers/base/devcoredump.c
@@ -0,0 +1,430 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright(c) 2014 Intel Mobile Communications GmbH
+ * Copyright(c) 2015 Intel Deutschland GmbH
+ *
+ * Contact Information:
+ * Intel Linux Wireless <ilw@linux.intel.com>
+ * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
+ *
+ * Author: Johannes Berg <johannes@sipsolutions.net>
+ */
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/devcoredump.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/workqueue.h>
+
+static struct class devcd_class;
+
+/* global disable flag, for security purposes */
+static bool devcd_disabled;
+
+/* if data isn't read by userspace after 5 minutes then delete it */
+#define DEVCD_TIMEOUT (HZ * 60 * 5)
+
+struct devcd_entry {
+ struct device devcd_dev;
+ void *data;
+ size_t datalen;
+ /*
+ * Here, mutex is required to serialize the calls to del_wk work between
+ * user/kernel space which happens when devcd is added with device_add()
+ * and that sends uevent to user space. User space reads the uevents,
+ * and calls to devcd_data_write() which try to modify the work which is
+ * not even initialized/queued from devcoredump.
+ *
+ *
+ *
+ * cpu0(X) cpu1(Y)
+ *
+ * dev_coredump() uevent sent to user space
+ * device_add() ======================> user space process Y reads the
+ * uevents writes to devcd fd
+ * which results into writes to
+ *
+ * devcd_data_write()
+ * mod_delayed_work()
+ * try_to_grab_pending()
+ * del_timer()
+ * debug_assert_init()
+ * INIT_DELAYED_WORK()
+ * schedule_delayed_work()
+ *
+ *
+ * Also, mutex alone would not be enough to avoid scheduling of
+ * del_wk work after it get flush from a call to devcd_free()
+ * mentioned as below.
+ *
+ * disabled_store()
+ * devcd_free()
+ * mutex_lock() devcd_data_write()
+ * flush_delayed_work()
+ * mutex_unlock()
+ * mutex_lock()
+ * mod_delayed_work()
+ * mutex_unlock()
+ * So, delete_work flag is required.
+ */
+ struct mutex mutex;
+ bool delete_work;
+ struct module *owner;
+ ssize_t (*read)(char *buffer, loff_t offset, size_t count,
+ void *data, size_t datalen);
+ void (*free)(void *data);
+ struct delayed_work del_wk;
+ struct device *failing_dev;
+};
+
+static struct devcd_entry *dev_to_devcd(struct device *dev)
+{
+ return container_of(dev, struct devcd_entry, devcd_dev);
+}
+
+static void devcd_dev_release(struct device *dev)
+{
+ struct devcd_entry *devcd = dev_to_devcd(dev);
+
+ devcd->free(devcd->data);
+ module_put(devcd->owner);
+
+ /*
+ * this seems racy, but I don't see a notifier or such on
+ * a struct device to know when it goes away?
+ */
+ if (devcd->failing_dev->kobj.sd)
+ sysfs_delete_link(&devcd->failing_dev->kobj, &dev->kobj,
+ "devcoredump");
+
+ put_device(devcd->failing_dev);
+ kfree(devcd);
+}
+
+static void devcd_del(struct work_struct *wk)
+{
+ struct devcd_entry *devcd;
+
+ devcd = container_of(wk, struct devcd_entry, del_wk.work);
+
+ device_del(&devcd->devcd_dev);
+ put_device(&devcd->devcd_dev);
+}
+
+static ssize_t devcd_data_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buffer, loff_t offset, size_t count)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct devcd_entry *devcd = dev_to_devcd(dev);
+
+ return devcd->read(buffer, offset, count, devcd->data, devcd->datalen);
+}
+
+static ssize_t devcd_data_write(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buffer, loff_t offset, size_t count)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct devcd_entry *devcd = dev_to_devcd(dev);
+
+ mutex_lock(&devcd->mutex);
+ if (!devcd->delete_work) {
+ devcd->delete_work = true;
+ mod_delayed_work(system_wq, &devcd->del_wk, 0);
+ }
+ mutex_unlock(&devcd->mutex);
+
+ return count;
+}
+
+static struct bin_attribute devcd_attr_data = {
+ .attr = { .name = "data", .mode = S_IRUSR | S_IWUSR, },
+ .size = 0,
+ .read = devcd_data_read,
+ .write = devcd_data_write,
+};
+
+static struct bin_attribute *devcd_dev_bin_attrs[] = {
+ &devcd_attr_data, NULL,
+};
+
+static const struct attribute_group devcd_dev_group = {
+ .bin_attrs = devcd_dev_bin_attrs,
+};
+
+static const struct attribute_group *devcd_dev_groups[] = {
+ &devcd_dev_group, NULL,
+};
+
+static int devcd_free(struct device *dev, void *data)
+{
+ struct devcd_entry *devcd = dev_to_devcd(dev);
+
+ mutex_lock(&devcd->mutex);
+ if (!devcd->delete_work)
+ devcd->delete_work = true;
+
+ flush_delayed_work(&devcd->del_wk);
+ mutex_unlock(&devcd->mutex);
+ return 0;
+}
+
+static ssize_t disabled_show(struct class *class, struct class_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%d\n", devcd_disabled);
+}
+
+/*
+ *
+ * disabled_store() worker()
+ * class_for_each_device(&devcd_class,
+ * NULL, NULL, devcd_free)
+ * ...
+ * ...
+ * while ((dev = class_dev_iter_next(&iter))
+ * devcd_del()
+ * device_del()
+ * put_device() <- last reference
+ * error = fn(dev, data) devcd_dev_release()
+ * devcd_free(dev, data) kfree(devcd)
+ * mutex_lock(&devcd->mutex);
+ *
+ *
+ * In the above diagram, It looks like disabled_store() would be racing with parallely
+ * running devcd_del() and result in memory abort while acquiring devcd->mutex which
+ * is called after kfree of devcd memory after dropping its last reference with
+ * put_device(). However, this will not happens as fn(dev, data) runs
+ * with its own reference to device via klist_node so it is not its last reference.
+ * so, above situation would not occur.
+ */
+
+static ssize_t disabled_store(struct class *class, struct class_attribute *attr,
+ const char *buf, size_t count)
+{
+ long tmp = simple_strtol(buf, NULL, 10);
+
+ /*
+ * This essentially makes the attribute write-once, since you can't
+ * go back to not having it disabled. This is intentional, it serves
+ * as a system lockdown feature.
+ */
+ if (tmp != 1)
+ return -EINVAL;
+
+ devcd_disabled = true;
+
+ class_for_each_device(&devcd_class, NULL, NULL, devcd_free);
+
+ return count;
+}
+static CLASS_ATTR_RW(disabled);
+
+static struct attribute *devcd_class_attrs[] = {
+ &class_attr_disabled.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(devcd_class);
+
+static struct class devcd_class = {
+ .name = "devcoredump",
+ .owner = THIS_MODULE,
+ .dev_release = devcd_dev_release,
+ .dev_groups = devcd_dev_groups,
+ .class_groups = devcd_class_groups,
+};
+
+static ssize_t devcd_readv(char *buffer, loff_t offset, size_t count,
+ void *data, size_t datalen)
+{
+ return memory_read_from_buffer(buffer, count, &offset, data, datalen);
+}
+
+static void devcd_freev(void *data)
+{
+ vfree(data);
+}
+
+/**
+ * dev_coredumpv - create device coredump with vmalloc data
+ * @dev: the struct device for the crashed device
+ * @data: vmalloc data containing the device coredump
+ * @datalen: length of the data
+ * @gfp: allocation flags
+ *
+ * This function takes ownership of the vmalloc'ed data and will free
+ * it when it is no longer used. See dev_coredumpm() for more information.
+ */
+void dev_coredumpv(struct device *dev, void *data, size_t datalen,
+ gfp_t gfp)
+{
+ dev_coredumpm(dev, NULL, data, datalen, gfp, devcd_readv, devcd_freev);
+}
+EXPORT_SYMBOL_GPL(dev_coredumpv);
+
+static int devcd_match_failing(struct device *dev, const void *failing)
+{
+ struct devcd_entry *devcd = dev_to_devcd(dev);
+
+ return devcd->failing_dev == failing;
+}
+
+/**
+ * devcd_free_sgtable - free all the memory of the given scatterlist table
+ * (i.e. both pages and scatterlist instances)
+ * NOTE: if two tables allocated with devcd_alloc_sgtable and then chained
+ * using the sg_chain function then that function should be called only once
+ * on the chained table
+ * @table: pointer to sg_table to free
+ */
+static void devcd_free_sgtable(void *data)
+{
+ _devcd_free_sgtable(data);
+}
+
+/**
+ * devcd_read_from_table - copy data from sg_table to a given buffer
+ * and return the number of bytes read
+ * @buffer: the buffer to copy the data to it
+ * @buf_len: the length of the buffer
+ * @data: the scatterlist table to copy from
+ * @offset: start copy from @offset@ bytes from the head of the data
+ * in the given scatterlist
+ * @data_len: the length of the data in the sg_table
+ */
+static ssize_t devcd_read_from_sgtable(char *buffer, loff_t offset,
+ size_t buf_len, void *data,
+ size_t data_len)
+{
+ struct scatterlist *table = data;
+
+ if (offset > data_len)
+ return -EINVAL;
+
+ if (offset + buf_len > data_len)
+ buf_len = data_len - offset;
+ return sg_pcopy_to_buffer(table, sg_nents(table), buffer, buf_len,
+ offset);
+}
+
+/**
+ * dev_coredumpm - create device coredump with read/free methods
+ * @dev: the struct device for the crashed device
+ * @owner: the module that contains the read/free functions, use %THIS_MODULE
+ * @data: data cookie for the @read/@free functions
+ * @datalen: length of the data
+ * @gfp: allocation flags
+ * @read: function to read from the given buffer
+ * @free: function to free the given buffer
+ *
+ * Creates a new device coredump for the given device. If a previous one hasn't
+ * been read yet, the new coredump is discarded. The data lifetime is determined
+ * by the device coredump framework and when it is no longer needed the @free
+ * function will be called to free the data.
+ */
+void dev_coredumpm(struct device *dev, struct module *owner,
+ void *data, size_t datalen, gfp_t gfp,
+ ssize_t (*read)(char *buffer, loff_t offset, size_t count,
+ void *data, size_t datalen),
+ void (*free)(void *data))
+{
+ static atomic_t devcd_count = ATOMIC_INIT(0);
+ struct devcd_entry *devcd;
+ struct device *existing;
+
+ if (devcd_disabled)
+ goto free;
+
+ existing = class_find_device(&devcd_class, NULL, dev,
+ devcd_match_failing);
+ if (existing) {
+ put_device(existing);
+ goto free;
+ }
+
+ if (!try_module_get(owner))
+ goto free;
+
+ devcd = kzalloc(sizeof(*devcd), gfp);
+ if (!devcd)
+ goto put_module;
+
+ devcd->owner = owner;
+ devcd->data = data;
+ devcd->datalen = datalen;
+ devcd->read = read;
+ devcd->free = free;
+ devcd->failing_dev = get_device(dev);
+ devcd->delete_work = false;
+
+ mutex_init(&devcd->mutex);
+ device_initialize(&devcd->devcd_dev);
+
+ dev_set_name(&devcd->devcd_dev, "devcd%d",
+ atomic_inc_return(&devcd_count));
+ devcd->devcd_dev.class = &devcd_class;
+
+ mutex_lock(&devcd->mutex);
+ dev_set_uevent_suppress(&devcd->devcd_dev, true);
+ if (device_add(&devcd->devcd_dev))
+ goto put_device;
+
+ if (sysfs_create_link(&devcd->devcd_dev.kobj, &dev->kobj,
+ "failing_device"))
+ /* nothing - symlink will be missing */;
+
+ if (sysfs_create_link(&dev->kobj, &devcd->devcd_dev.kobj,
+ "devcoredump"))
+ /* nothing - symlink will be missing */;
+
+ dev_set_uevent_suppress(&devcd->devcd_dev, false);
+ kobject_uevent(&devcd->devcd_dev.kobj, KOBJ_ADD);
+ INIT_DELAYED_WORK(&devcd->del_wk, devcd_del);
+ schedule_delayed_work(&devcd->del_wk, DEVCD_TIMEOUT);
+ mutex_unlock(&devcd->mutex);
+ return;
+ put_device:
+ put_device(&devcd->devcd_dev);
+ mutex_unlock(&devcd->mutex);
+ put_module:
+ module_put(owner);
+ free:
+ free(data);
+}
+EXPORT_SYMBOL_GPL(dev_coredumpm);
+
+/**
+ * dev_coredumpsg - create device coredump that uses scatterlist as data
+ * parameter
+ * @dev: the struct device for the crashed device
+ * @table: the dump data
+ * @datalen: length of the data
+ * @gfp: allocation flags
+ *
+ * Creates a new device coredump for the given device. If a previous one hasn't
+ * been read yet, the new coredump is discarded. The data lifetime is determined
+ * by the device coredump framework and when it is no longer needed
+ * it will free the data.
+ */
+void dev_coredumpsg(struct device *dev, struct scatterlist *table,
+ size_t datalen, gfp_t gfp)
+{
+ dev_coredumpm(dev, NULL, table, datalen, gfp, devcd_read_from_sgtable,
+ devcd_free_sgtable);
+}
+EXPORT_SYMBOL_GPL(dev_coredumpsg);
+
+static int __init devcoredump_init(void)
+{
+ return class_register(&devcd_class);
+}
+__initcall(devcoredump_init);
+
+static void __exit devcoredump_exit(void)
+{
+ class_for_each_device(&devcd_class, NULL, NULL, devcd_free);
+ class_unregister(&devcd_class);
+}
+__exitcall(devcoredump_exit);